The present invention relates to a method of mixing fluids. More particularly, the present invention is a method of mixing viscous fluids by rotating a multi-vaned mixer.
The mixing of viscous fluids has historically been a difficult task. Present methods of mixing such fluids often result in inadequate mixing and are time-consuming and energy consumptive.
One of the more common viscous fluids which must be mixed is paint. Homeowners and painters are all too familiar with the task of mixing paint.
Probably the most common method of mixing fluid such as paint involves the user opening the container, inserting a stir stick or rod and rotating or moving the stick about the container. This method is tiring, requiring tremendous effort to move the stir stick through the viscous fluid. Because of this, individuals often give up and stop mixing long before the paint is adequately mixed. Further, even if the individual moves the stir stick for a long period of time, there is no guarantee that the paint is thoroughly mixed, rather than simply moved about the container.
Many mechanisms have been proposed for mixing these fluids and reducing the manual labor associated with the same. These mechanisms have all suffered from at least one of several drawbacks: users have difficulty in using the device because of its complexity or size, the device inadequately mixes the fluid, the device mixes too slowly, the device does not break up or xe2x80x9cdispersexe2x80x9d clumped semi-solids in the fluid, and/or the user has a difficult time cleaning up the device after using it. Other problems associated with these mixers are that they often introduce air into the fluid (which, in the case of paint is detrimental, for example, when the paint is to be sprayed with a sprayer), and some of the mixing devices may damage the container in which the fluid is being mixed, causing the fluid to leak from the container.
One example of such a mechanized mixing device is essentially a xe2x80x9cscrewxe2x80x9d or auger type device. An example of such a device is illustrated in U.S. Pat. No. 4,538,922 to Johnson. This device is not particularly effective in mixing such fluids, as it imparts little velocity to the fluid. Further, the device does not disperse clumped fluid material, but simply pushes it around the container.
Another method for mixing paint comprises shaking the paint in a closed container. This can be done by hand, or by expensive motor-driven shakers. In either instance, the mixing is time consuming and often not complete. Because the shaking occurs with the container closed, little air space is available within the container for the fluid therein to move about. Therefore, the shaking often tends to move the fluid very little within the container.
Several devices have been developed for mixing paint which comprise devices for connection to drills. For example, U.S. Pat. No. 4,893,941 to Wayte discloses a mixing device which comprises a circular disc having vanes connected thereto. The apparatus is rotated by connecting a drill to a shaft which is connected to the disc. This device suffers from drawbacks. First, the limited number of vanes does not provide for thorough mixing. Second, because the bottom disc is solid, no fluid is drawn through the device from the bottom. It is often critical that fluid from the bottom of the container be drawn upwardly when mixing viscous fluids, since this is where the heaviest of the fluids separate prior to mixing.
U.S. Pat. No. 3,733,645 to Seiler discloses a paint mixing and roller mounting apparatus comprising a star-shaped attachment. This apparatus is not effective in mixing paint, as it does not draw the fluid from the top and bottom of the container. Instead, the paddle-like construction of the device simply causes the fluid to be circulated around the device.
U.S. Pat. No. 1,765,386 to Wait discloses yet another device for mixing liquids. This device is wholly unacceptable, as it must be used in conjunction with a diverter plate located in the container to achieve adequate mixing. Use of the diverter plate would either require its installation into a paint container before being filled, which would increase the cost of paint to the consumer, or require that the consumer somehow install the device into a full paint container.
An inexpensive method for mixing viscous fluids in a quick and effective manner is needed.
The present invention is a method of mixing viscous fluids. The method comprises locating a mixing device in a container of fluid and rotating said device in said fluid with rotary drive means. The mixing device preferably comprises a mixing cage connected to the shaft.
The shaft is elongate, having a first end connected to a central plate and a second free end for connection to the rotary drive means. The plate is solid, circular, and has a top side, bottom side, and outer edge.
Vanes in the form of thin, curved slats, are spacedly positioned about the outer edge of each side of the plate. The vanes extend outwardly from each side of the plate parallel to the shaft. A first end of each vane is connected to the plate near the outer edge thereof. The vanes are connected at their second ends by a hoop.
The vanes preferably have a length which is between about 0.1-2 times the diameter of the plate. The number of vanes located about each side of the plate preferably number between 4 and 12 per inch diameter of the plate. Each vane preferably extends inwardly from the periphery of the plate no more than about 0.1-0.35 of the distance from the center of the plate to the periphery thereof at that location.
In use, a user positions the mixing cage of the device in a container of fluid. The user connects the free end of the shaft to the rotary drive means, such as a drill, and rotates the cage within the fluid.
The device has been found to be extremely effective in mixing viscous fluids such as paint. The device draws fluid, without the need of a diverter plate, from the top and bottom of the container. The fluid is dispersed at high velocity radially outwardly through vanes.
The device is easy to use, and a user need only connect it to a drill. The device is easy to clean, the user needing only to relocate it and rotate it in a container of cleaning fluid.
Further objects, features and advantages of the present invention over the prior art will become apparent from the detailed description of the drawings which follows, when considered with the attached figures.